Abstract ID: 17276 Title: Ultrasound Symposium
Visualization of breast carcinoma using photoacoustic imaging: the ongoing Twente
experience
Michelle Heijblom1,2, Daniele Piras1, Wenfeng Xia1, Johan Van Hespen1, Frank van den
Engh2, Joost Klaase2, Ton van Leeuwen1,3, Wiendelt Steenbergen1 and Srirang Manohar1, *
1
Biomedical Photonic Imaging Group, University of Twente, Enschede, The Netherlands
2
Centre for Breast Care, Medisch Spectrum Twente, Enschede, The Netherlands
3
Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam,
The Netherlands
*
Presenting author
Purpose:
Worldwide, every year more than 1,300,000 women are diagnosed with breast cancer and
annually, about 450,000 women die from the disease [1]. However, the current practice of
imaging the breast for the detection and diagnosis of cancer suffers from shortcomings [2].
The interactions of the probe energy—whether X-rays, magnetic field, or ultrasound (US)—
with a tumor are not sufficiently specific or sensitive compared with non-pathological tissue.
This results in occurrences of false positives and false negatives, which lead to psychological
and physical morbidity and mortality. Furthermore, though X-ray mammography is the gold
standard imaging modality, X-rays are carcinogenic. Ultrasound and MRI are restricted in
their use to being secondary procedures owing to low sensitivity (US), poor specificity (MRI),
and high-expense (MRI). There is thus a requirement for a technique that is relatively
harmless and has the potential to detect the presence of carcinoma in a manner that is more
specific and reliable than inspection of morphologic and anatomic changes.
Methods
Photoacoustic imaging has much potential in detecting the presence of a carcinoma based on
the optical absorption contrast manifested by the tumor compared to healthy tissue. This
higher absorption is due to the presence of blood contents in the enhanced vascularization
associated with the growth and spread of cancer. In PA, short pulses of light are used to
illuminate the tissue: absorption induces heating followed by rapid thermal expansion. This
generates US waves that propagate through tissue, to be detected by acoustic transducers
positioned at the surface. The time-of-flight (TOF), amplitude and duration of acoustic pulses
recorded on the tissue surface possess information regarding the location, absorption, and
dimensions of the source. By recording signals in a 2-D grid of detector positions, a 3-D
reconstruction of the absorber is possible. The advantage of this approach compared with
purely optical imaging is that the spatial resolution is superior because of the low scattering
experienced by the US during propagation in soft tissue.
In the Biomedical Photonic Imaging Group (BMPI) of the University of Twente (UT)
we have worked to develop photoacoustic imaging for breast imaging [3]. In 2007, the BMPI
group reported their first results of NIR photoacoustic imaging of breast cancer in human
subjects: in 4 of 5 cases of suspect breasts higher photoacoustic contrast associated was
observed [4].
Results
In December 2010, a new clinical study has been started at the Centre for Breast Care of the
Medisch Spectrum Twente in Oldenzaal. In this study, a number of patients will be measured
within a period of 1.5 years. Patients are measured within the normal diagnostic path at the
Centre for Mammacare, in between the ultrasound investigation and the ultrasound guided
biopsy.
Abstract ID: 17276 Title: Ultrasound Symposium
The study can be divided into three phases and for each phase patients are included
based on the suspiciousness of their lesion. In the Phase 1 of the study, the focus is on a small
number of patients with lesions that are highly suspicious for malignancy. The goal of this
part of the study is to optimize the imaging methods for the visualization of malignancies.
At the time of going to press Phase 1 has been successfully completed. Ten technically
acceptable measurements have been performed all of breasts highly suspect for malignancy
[5]. The photoacoustic images have been compared with conventional imaging methods such
as X-ray imaging, ultrasound imaging and in some cases Magnetic Resonance Imaging.
Conclusions
These results confirm the conclusions of the 2007 study: that NIR photoacoustic imaging has
potential in the diagnosis of breast cancer. On-going work involves imaging patients in the
subsequent phases. In phase 2 of the study, a large number of patients with lesions that are
suspicious for malignancy are measured in order to define the photoacoustic markers that are
indicative for the presence of a malignancy. In the last phase of the study, the absence of those
photoacoustic malignancy markers will be verified in subjects with either healthy breast tissue
or benign lesions.
References:
1 Tirona, M. T., Sehgal, R. & Ballester, O. Prevention of breast cancer (part I):
epidemiology, risk factors, and risk assessment tools. Cancer Invest 28, 743-750 (2010).
2 Nothacker, M., Duda, V., Hahn, M., Warm, M., Degenhardt, F., Madjar, H., Weinbrenner,
S. & Albert, U. S. Early detection of breast cancer: benefits and risks of supplemental
breast ultrasound in asymptomatic women with mammographically dense breast tissue. A
systematic review. Bmc Cancer 9, - (2009).
3 Manohar, S., Kharine, A., van Hespen, J. C. G., Steenbergen, W. & van Leeuwen, T. G.
The Twente Photoacoustic Mammoscope: system overview and performance. Physics in
Medicine and Biology 50, 2543-2557 (2005).
4 Manohar, S., Vaartjes, S. E., van Hespen, J. C. G., Klaase, J. M., van den Engh, F. M.,
Steenbergen, W. & van Leeuwen, T. G. Initial results of in vivo non-invasive cancer
imaging in the human breast using near-infrared photoacoustics. Optics Express 15, 1227712285 (2007).
5 Heijblom, M. et al (2011) in preparation